(a) Field of the Invention
The present invention relates to a lift device of the type having a vertical column provided with a movable support frame for lifting an object supported thereon and to one side of the column.
More specifically, but not exclusively, the present invention relates to a lift device of the type comprising two spaced apart vertical columns each having a support frame for lifting a vehicle therebetween and above a support surface.
B. Description of the Prior Art
Known lift devices for lifting vehicles are normally of the type having a hydraulic piston secured in a floor and having a support frame at the upper end thereof to engage the undercarriage of a vehicle to lift it up from the ground by hydraulic pressure which causes the cylinder to rise from the ground. In order to install such a lift device, it is necessary to excavate a hole in the ground having approximately 4 feet in diameter and 8 feet in depth. A concrete foundation is poured at the bottom thereof to support the cylinder in the hole. Some of the problems encountered with this type of lift device is that it is sometimes very costly to excavate if one encounters rock and has to blast a hole in a service station. Further, the support cylinder of such device is normally positioned centrally of a work area and is therefore an obstruction to a person working under the vehicle. Still further, the support frame being supported from the center of the undercarriage of the vehicle extends over certain parts of undercarriage of the vehicle which are required to be serviced, such as the transmission, muffler, etc., and thus being cumbersome. Still further, such lift devices require periodic servicing or maintenance to make sure that it operates satisfactorily. It is also necessary to purchase a compressor whereby to make the cylinder function. Thus, this type of lift device is costly to install and maintain.
Another type of lift device known is that utilizing two vertical columns, each having a support frame which is movable along the column whereby to lift a vehicle from opposed sides and between the columns above a support surface. With this type of lift device, there is no obstruction under the vehicle when it is lifted by the support frames. However, a disadvantage of such known type of vertical column lift device is that it is very costly to construct and utilizes large motors to drive a threaded bolt which displaces the support frames. Still further, the support frames are interconnected to each other by a linkage extending above a support surface thus causing an obstacle on the support surface between the two vertical columns. Such obstacle is hazardous to a person repairing a vehicle particularly when the person is holding an instrument in his hands. Furthermore, the drive motors for such devices are considerably large, utilize high voltages not normally available in service stations and costly. The manner in which the support members are raised is further complicated and expensive to construct. Still further, the safety features of such known device are not satisfactory, and the lift operates very slowly.